Complement factor C3a, whose generation depends on adipsin level, can bind with the C3a receptor and activate the Ca2+ signaling pathway in pancreatic β cells, thereby accelerating insulin secretion. Obese individuals and T2DM patients exhibit lower circulating adipsin levels, which is thought of as a monitoring factor for patients in the prediabetic state. The gene discussed is CFD; the disease is type 2 diabetes mellitus.